An electrical switching device is disclosed.
In particular, a miniature circuit breaker is disclosed which can be used for disconnecting loads in the event of a short-circuit or overcurrent. Naturally, the breaker can also be used in combination with motor circuit breakers and with residual current devices.
A miniature circuit breaker has in its interior an electromagnetic release with a plunger-type electromagnet, with a core and a moving armature around which a coil is wound. In the case of a short circuit, the armature moves and, on the one hand, strikes the contact lever so that the contact point is rapidly opened; on the other hand, it also provides long-term opening of the contact point via a latch. The thermal release which is in the form of a bimetallic release in most cases acts exclusively on the latch to effect the long-term opening of the contact point. The bimetallic strip is in most cases a strip which bends due to the different coefficients of expansion of the metals joined to one another. Naturally, a strip of a shape memory alloy can also be used instead of a thermal bimetallic strip.
In the switch S2 from the company ABB Stotz Kontakt GmbH, Heidelberg, the latch is supported between two boards which are connected to one another and also have or accommodate the bearing points for the corresponding components forming the latching point. In this switch, the electromagnetic release is located between the thermal bimetallic strip and the contact lever, i.e. the contact lever is located on one side and the thermal bimetallic strip on the other.